You don't know til you try . . .

FBus Part Deux

, posted: 25-Oct-2009 09:54

some keywords - avr bascom fbus version 3 nokia 1202 gnokii serial monitor gsm dialling

Went hunting for a cable so I would not have to dismantle a new phone for testing.
Phone shop under the IAMX on queent st, not very helpful.
Omni in Henderson, same.
Parallel Imports next door, same.

Naturally as soon as I mentioned the model of the phone, they turned off.
Too low end they said.

Picked up a cable via Trademe. Nokia CA-45 clone.

Looked about right. Not right enough though.
The plug was too big.

A little modifying will fix that.
The pin spacing looked ok.
While it should work I did not bother as I would still need to connect a ground elsewhere.
Photobucket Photobucket Photobucket

I have concluded the proper cable is not a consumer item, only a service tech item.

BUT it is a very cheap way to get a USB > RS232 (TTL level) converter.
I mean sub $10, that's hard to beat.
Won't be buying this anymore

The only problem with this cable is, the USB VCC/5v are not exposed.
No problem, get one that does. CA-42

What I really needed was a "Easy Flash Cable"

So back to what I was using and the old phone.
Looks like it was fine, just needed to keep the LCD connector pressed flat.
It is a glued on connection rather than the usual connector.

Found the user manual with examples for GNOKII, I did miss it the first time around.
Must have been tunnel vision
Photobucket Photobucket Photobucket

Can now also send SMS/TXTs

Now to get this working on the AVR.
Looked around for sample code to work off.
Googled , bascom fbus, avr fbus
Slightly useful

-more links to be posted when found-

Downloaded a serial port monitor to see what GNOKII was sending to the phone.
Photobucket Photobucket

Back to here for a 2nd/3rd/4th... reading

Downloaded GNOKII source for the phone command strings.
Photobucket Photobucket Photobucket Photobucket Photobucket

First thing was to find a suitable crystal so the AVR could do 115k serial ok.
Pulled it off one of my spare RFID readers. 22.1184Mhz

Didn't work at first.
The micro sent the int string but got no response.
After an hour of checking, monitoring, loopbacking, found problem.
I had to send the int sequence twice.
While the PC only needed to send it once, for some reason the micro needed to send it twice.

Now to make some nicely commented code to give back to the community.
Watch this space Wink

Update: After some time (4hrs) absorbing info I am now ready to write a quick VB program.
Once that works than I will port it over to the AVR.

Photobucket - Laptop + external 17" monitor dual setup
See it all makes sense now.
This version of FBUS is slightly different to the one disected on

Update 26 Oct: I now have it dialing from the AVR. Laughing
Will clean up the code a little and post.
I took some shortcuts to keep it lean so I could use a micro with less ram.
While I have inplimented full frame construction and all the commands, my notes should make easy for anyone to cary it on.

Also wrote a quick program to calculate the frame checksums.
Help greatly in debuggin the micro's code.

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Permalink to FBus Part Deux | Add a comment (3 comments) | Main Index

Comment by Hossam, on 15-Feb-2010 01:33

Hello, This is a very interesting page, i'm starting to interface Nokia 1202 to a microcontroller, but i'm afraid to buy it and fail to implement the fbus protocol, i can see that you have succeeded to dial and send sms to that phone. I will appreciate it if you can post the final result ( the worked FBUS protocol) Thank you Hossam

Author's note by MrWestie, on 15-Feb-2010 07:29

Downloaded GNOKII source for the phone command strings. :)  if they don't make sense use a serial sniffer. I will post the code later this week.

Comment by Alexis, on 20-Oct-2010 23:18

Hi Mr Westie and thank you for this helpfull article, well documented and nicely writen. I'm now facing a very simple problem related to your article : I'm trying to get data's from my NOKIA 2610 Phone. So, i basicly need the scematic of the CA-45 cable and drivers. Do you know where i can find this ? Thank you very much for your help. Alexis (from France)

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